Kevin,
I am just kinda torn as I am trying to make sense out of this.
I like your approach but I am trying to look at it from a different perspective.
In my mind, hypermedia is not orthogonal to discovery but complementary.
I do see the importance of a good discovery document that documents the API in a machine readable format with matching schemas.
Once that document is published, the application needs to define/use a mime-type.
Your recommendation seems to be: application/vnd.siren+json.
But wouldn't it be more likely to be something like:
application/vnd.myapp+json; describedby=myschema.rnc
The JSON format would still be Siren-like.. I think… may be with some additional simplification since a schema is also available…
I would like to get your feedback on this.
Many thanks,
Pat.